Dansgaard-Oeschger events in climate models - criteria for model assessment

Greenland ice core records feature Dansgaard–Oeschger (D-O) events; abrupt warming episodes followed by a gradual cooling phase during mid-glacial periods. Here, we analyse spontaneous self-sustained D-O type oscillations reproduced in four climate models: COSMOS, CCSM4, MPI-ESM and HadCM3. We assess model performance against several metrics: rate of Antarctic warming during D-O stadials, timing of change point in Antarctic temperature with respect to the mid-point of the Greenland transition, duration of the D-O event and Intertropical Convergence Zone (ITC) position. The four models suggest consistently that the amplitude and spatial expression of D-O event temperature anomalies are dominated by coupled changes in the Atlantic Meridional Overturning Circulation (AMOC) and North Atlantic sea ice extent.